Below is a concise list of key definitions from Chapter 5: Circular Motion

Below is a concise list of key definitions from Chapter 5: Circular Motion of the 11th Class Physics syllabus for the Federal Board of Intermediate and Secondary Education (FBISE), aligned with the National Book Foundation (NBF) curriculum. These definitions cover the essential concepts related to circular motion as typically presented in this chapter.

1. Circular Motion: The motion of an object along a circular path, where the object moves at a constant distance from a fixed point (center).
2. Uniform Circular Motion: Circular motion in which an object moves with constant speed along a circular path, though its velocity changes due to changing direction.
3. Angular Displacement (θ): The angle through which an object moves in circular motion, measured in radians, defined as θ = s/r, where s is the arc length and r is the radius.
4. Radian: A unit of angular measure, where 1 radian is the angle subtended by an arc equal in length to the radius (1 rad ≈ 57.3°).
5. Angular Velocity (ω): The rate of change of angular displacement with time, given by ω = Δθ/Δt, measured in radians per second (rad/s).
6. Angular Acceleration (α): The rate of change of angular velocity with time, given by α = Δω/Δt, measured in radians per second squared (rad/s²).
7. Centripetal Acceleration: The acceleration directed toward the center of a circular path, responsible for changing the direction of velocity, given by a_c = v²/r, where v is speed and r is radius.
8. Centripetal Force: The net force acting toward the center of a circular path, causing centripetal acceleration, given by F_c = mv²/r, where m is mass, v is speed, and r is radius.
9. Centrifugal Force: An apparent (fictitious) force experienced in a non-inertial frame, seeming to push an object outward during circular motion (not a real force).
10. Period (T): The time taken by an object to complete one full revolution in circular motion, measured in seconds.
11. Frequency (f): The number of revolutions completed per unit time, given by f = 1/T, measured in hertz (Hz).
12. Tangential Velocity: The linear velocity of an object in circular motion, directed along the tangent to the circular path, given by v = rω, where r is radius and ω is angular velocity.
13. Moment of Inertia (I): A physical property of a rotating object that quantifies its resistance to angular acceleration, given by I = Σmr², where m is mass and r is the distance from the axis of rotation.
14. Angular Momentum (L): A vector quantity representing the rotational analog of linear momentum, given by L = Iω, where I is moment of inertia and ω is angular velocity.
15. Law of Conservation of Angular Momentum: The angular momentum of a system remains constant if no external torque acts on it, expressed as Iω = constant.
16. Torque (τ): A rotational force that causes angular acceleration, given by τ = r × F, where r is the perpendicular distance from the axis and F is the force.
17. Banking of Roads: The tilting of a road’s surface at curves to reduce the reliance on friction for centripetal force, with an optimal angle given by tanθ = v²/rg, where v is speed, r is radius, and g is gravitational acceleration.
18. Conical Pendulum: A mass moving in a horizontal circle while attached to a string fixed at a point, maintaining a constant angle with the vertical, used to study circular motion.

These definitions cover the core concepts of circular motion from Chapter 5 of the FBISE 11th Class Physics curriculum. If you need further clarification or additional terms, feel free to ask!